Trying for a somewhat more gracious response to
@tetrasodium:
You seem to have latched onto the fact that these things ended in the same place, which I have already clarified was simply a matter of conforming to what actually happened in my campaign. I don't recall whether the actual process involved discussing the Ritual move or not, as I said. The players took the lead on this. They actually went to several more locations than the ones I listed, I just wanted to keep it sufficiently light on detail to not bog down the discussion.
But, since it seems the issue at hand is the presumption that these three scenarios ending in the same place means the DM had pre-chosen an ending, which was not my intention, sure, we can break that symmetry. It will make the examples harder to compare, but sure. For brevity, I won't write it out as full dialogue, just as a quick summary. Again, this is based on stuff that actually happened in my game.
Situation: the players are trying to take down a woman who has cooperated with a wicked succubus, and said succubus who is dabbling in devil-like contracts in addition to her usual temptations in order to become something more powerful than either demon or devil alone.
"Full" MMI
Players propose, in sequence, the following actions: tail the woman (doesn't work, the woman is supernaturally good at evading detection, probably a succubus power), consult Waziri tomes on the subject (information on demons is restricted and party isn't trusted enough to read it), try to contact the succubus to whom the tiefling bard is related (she's busy and can't help right now), use divination magic to figure out where the succubus is (fails without explicit explanation because the succubus isn't actually on the mortal plane), consult with Safiqi priests on how to exorcise demons (same as library), examine public records of the woman's multiple deceased spouses to find any patterns (fails because the records aren't actually public.) Finally, the players propose the solution the DM had approved all along, breaking into her home while she's out at a party so they can find the demon-altar where she performs her rituals, set a trap on it to kill both, and then lie in wait for the woman to return. The players enjoy the difficulty of sneaking in without alerting any of the guards or putting the innocent servants at risk, and by the end, make preparations for an Epic Showdown Fight.
Here, MMI is used clearly in service of railroading, but both parts (denying plausible actions
and forcing a specific outcome) are a problem. Every proposed solution is shut down until the players, grasping at straws, stumble upon the one "intended" solution, which was necessary so the DM could deploy the two important bits of prepared content (the stealth infiltration and surprising the woman and the succubus.)
"Light" MMI
Players propose, in sequence, the following actions: tail the woman (they attempt to, but must roll Defy Danger with WIS every single round,* meaning eventually they get a 6- and she eludes them), consult Waziri tomes on the subject (they are allowed access to generic information, which doesn't reveal anything useful), try to contact the succubus to whom the tiefling bard is related (she's willing to meet, but has to get approval from the convent), use divination magic to figure out where the succubus is (they learn she isn't located on the mortal plane, but rather spends most of her time in Hell/the Abyss other than brief forays into the mortal world), consult with Safiqi priests on how to exorcise demons (they are offered exorcism training, but only one person gets even a partial success on Spout Lore, so they don't actually learn the process), consult public records of the woman's multiple deceased spouses to find any patterns (most records are sealed, though they do see some records of the house's original occupant long ago having requested some interesting renovation stuff.) This final thing nudges the party into infiltrating in the dead of night while the lady of the house is at a late-night party, so the guards and servants are gone. While they don't know how to
exorcise the demon, they find her altar. Deciding that discretion is the better part of valor, they take detailed notes of the altar's construction and location and then depart, hoping that with actual
proof of demonic activity, they can get the Safiqi to help them with the problem.
Here we see a lot of what I've called "covert" MMI. The DM may have genuinely been
trying to respect player agency, simply seeing his adjudications as fair and appropriate for the context, but it cashes out as
finding ways to say "no" until the party does the one thing the DM knows will work, even if that isn't his intent. There's no specially-prepared content awaiting them, and the players decide to come back later rather than force a fight right away. There's much less outright railroading, but still plenty of
effective stonewalling even though the players are not
technically told they can't do any of the things involved. The players might not even notice that MMI is in play if this is an unusual one-off, but if this is typical of the game's pattern, annoyance is likely to build up over time, as they come to believe they have to read the DM's mind.
*Technically, this is against both the spirit
and the rules of Dungeon World, but it's the closest approximation I can make of "make a Perception check every round," because...DW just
doesn't do that, not normally anyway. This is an example of the rules themselves discouraging a particular bad DM action; you have to intentionally go off-label in order to do the crappy thing.
Zero MMI
The PCs learn the woman basically only goes to parties or stays at home, and on interacting with her, they find her quite pleasant and circumspect--she's a model guest and a sparkling conversationalist. Suspicious but unsure, they pay a visit to the tiefling Bard's succubus great-grandmother, who is happy to meet with her great-grandson. She offers her help, and explains things the party can do. However, the Bard doesn't want to put his great-grandmother at risk, so he instead asks her if she can grant him her powers. She does. They seek a private meeting with the woman, see if she can be reasoned with. They discover, to everyone's surprise (due to a very favorable roll), that the woman is actually an innocent victim manipulated and coerced by the succubus, and she gladly offers to help them take down this demon who has plagued her life. The Ranger, recently anointed as a devotee of the Resolute Seeker, independently consults old Safiqi records and finds a disused technique for isolating places from planar travel as part of exorcism (no roll needed, but
using the technique will require one). Forearmed so, they prepare for a showdown with this empowered succubus.
Nothing pre-determined here, except by already-established backstory (e.g. it had always been the case, since the first month of the game, that the Bard's maternal great-grandmother was a succubus) which was authored by the players, or general knowledge established in previous adventures. The above is actually pretty much exactly what happened in-game, albeit at a fairly high level of abstraction.
Each path is quite different, this isn't a situation where the end state is identical for each one. Does that satisfy your desire that the DM be open to what the players want? Because, lest we forget,
the whole point of MMI is that it DOESN'T embrace what the players want to attempt. It closes off option after option for one reason or another (usually, because the option doesn't meet a ridiculously high standard of "realism" or "making sense" etc., or because the DM has an excessively skeptical position about anything the players might attempt that could give them "power" etc.)